Vinyl chloride (CH.sub.2 .dbd.CHCl) is prepared using a number of well known processes. Two familiar processes are (1) the hydrochlorination of acetylene and (2) the oxychlorination of ethylene to form dichloroethane which in turn is dehydrohalogenated to form vinyl chloride (see C. A. Schildknecht, Vinyl and Related Polymers, John Wiley and Sons, Inc. N.Y., N.Y. (1952), pages 388-390 and U.S. Pat. No. 2,847,483). As acetylene is more expensive than ethylene, the latter process is economically favored, and much activity is noted in this art area (see U.S. Pat. Nos. 3,634,330; 3,454,663; 3,448,057; and 3,624,170). Ethylene, in turn, can be prepared by the oxydehydrogenation of ethane (see U.S. Pat. No. 3,769,362). Although high yields of ethylene are particularly desired, processes which use ethane as a feed stock can produce not only ethylene, but also can directly produce vinyl chloride and other valuable products such as ethylene dichloride, ethyl chloride, and the like. The ethylene, ethylene dichloride, and ethyl chloride can be readily reacted to form more vinyl chloride.
The present invention is directed to an improved process for the preparation of ethylene and vinyl chloride from ethane which process employs a solid solution catalyst containing iron stabilized with lanthanum and/or lanthanides and modified with select metal cations. The catalysts exhibit improved activity and/or long lifetime. Catalysts containing iron or lanthanum are known to the art; see U.S. Pat. Nos. 3,907,713; 3,849,339; 3,769,362; 3,703,593; 3,658,934; 3,658,933; 3,207,809; 2,847,483; and 2,674,633; and British Pat. No. 1,039,369. However, none of these patents disclose a solid solution catalyst. An article in the Journal of The American Ceramic Society, Vol. 43, No. 7 (1960), page 367, discloses compounds of lanthanum and iron. A recently issued patent, U.S. Pat. No. 3,904,553, discloses certain specific solid solutions as catalysts.